Weighted artificial silk and method of its production



Patented May 31, 1927.

U ED" "STATES.

' 1,631,062 PATENT". orrlcs.

- GEORGE RIVA'I', OI PA'IEESON, NEW JERSEY, ASSIGNOR, BY MESNEASSIGNMENTS, TO LYONS PIECE DYE WORKS, OF PATERSON, NEW JERSEY, ACORPORATION OF NEW JERSEY.

wmon'rnn aa'rmromr. SILK AND METHOD or I'rs 'rnonuc'rron.

No Drawing.

or artificial fibers made of acetate ofcellu-. lose. This material,which usually containsfrom 50% to 52% of acetic acid bound "as an 'ester1 of cellulose, is practically-impermea'ble to water, and thereforeabs'orbs'buta very small proportion of the tin solution and of thesodium phosphate solution. Forin-l stance with one t e ofacetate'cellulosesilk now on the mar et, the maximum gain in:

weight obtainable with the ordinary treatment is 2%. The impermeabilityof this '20 special artificial silk, to aqueous solutions,

Qalso reduces its capacity to take u usual dyestuffs, in fact it isabsolutely re ractory to most dyestuffs.

The object of my present inventionis to improve the weighting treatmentto such an extent that vartificial silk of the type set forth may takeup a much higher percentage of the weighting agent (from thirty to morethan fifty times the maximum obtainable hitherto). W

In order to obtain these improved results,

I bring the acetate of cellulose into a state of gel, that is to say, Imodify its colloidal state so as to greatly increase its absorptivepower. A gelling agent is a product which swells. the cellulose acetatefibre and temporarily modifies its colloidal state by converting thecellulose acetate from a solid to a gel condition. When the fibre is ina gel state, it is particularly adapted to absorb other materials.

For the purposes of my resent invention,

cold aqueous solutions of ormicacid or of acetic acid, in concentrationsof from 15% to 20%, have been found veryeflicient as gellin agents,enabling the acetate of oellulose,fi rs to absorb readily not only basicdyestuffs, but the weighting agent (for example tin chloride) as well.The gelling agent is brought in contact with the fibers either beforethey are treated with the'tin chloride solution (or other weightingagent such as a-salt of any other heavy metal), or

weighting natural silk. This sodium sirable qualities.

treated remains soft and lustrous and'keeps' Application filed October15, 1925. Serial No. 62,588.

' during the weighting treatment, or both before and .during suchtreatment. When the gelling agent and the weighting agent are to actsimultaneously, the addition, for example, of seventy-five cubiccentimeters of acetic acid to one liter of the customary tin chloridesolution will be a suitable proport-ion.

Afterpas'sing through the tin'chloride solution '(tlll bath), theacetate of cellulose is washed carefull with water, thereby hy drolyzingthe tin completely on the fiber. After this washing no chlorine shouldbe found on the fiber.

The acetate of cellulose is then gelled again by passing through a coldaqueous formic acid solution of a strength of from 15% to 20%, thenwashed with water, and subse uently passed through a warm sodium phospate bath (at a temperature of from 40 to 45 centigrade), this sodiumhosphate treatment being performed "the same manner as is customary inthe case of phate bath is used for the purpose of xin the tin. After thefixing (phosphating treatment a further treatment with silicate of sodamay be employed in some cases, if

V desired.

The treatment consisting of, these steps of gelling, tin-weighting,washing, and fixing .(phosphatihg) and if desired, treating withsilicate of soda, may be repeated once or hosoftener to increase theamount of weighting 7 agent absorbed. Very high we'i hting percentagesmay thus be obtained, or instance 75%, 100%, or even more.

Acetate of cellulose products, when weight ed as describedabove, losenone of their de- The artificial silk thus all its original selectiveaflinities f0rdyestufi's. In fact, these affinities are enhanced, and inparticular the affinity for certain dye stufi's, such as the S. R. A.(sulfo ricinoleic acid dyestufis'),is increased very materially by theweightm treatment described.

I desire it to e understood that my invention is applicable to acetateof cellulose fibers or products irrespective of their condition, thatis, whether they be in the nature of threads, skeins, fabrics, etc.Furthermore, these fibers may be treated either alone, or

in conjunction with others, as for instance in the case of mixedwovenfabrics'which consist only partly ofacetate of cellulose. Variousmodifications may be made without departing from the nature of myinvention as set forth in the appended claims.

What is claimed is:

1. The process which comprises treating cellulose acetate silk with agelling agent and with a weighting agent.

2. The process which comprises treating cellulose acetate silk with .agelling agent and with a weighting agent comprising a suitable salt of aheavy metal.

3. The process which comprises treating cellulose acetate silk with agelling agent and with a tin chloride weighting solution.

'4. The process which comprises treating cellulose acetate silk with agelling. agent and with a tin chloride weighting solution, then washingthe product thus treated, and

then treating it with a suitable fixing agent.

5. The process which comprises treating cellulose acetate silk withagelling agent and with a tin chloride weighting solution, then washingthe product thus treated, then again treating with a gelling agent, and

I thereupon treating the product with a suitable fixing agent.

6. The process which comprises treating cellulose acetate silk with agelling agent and with a weighting agent, washing the product thustreated, again treating with a gelling agent, and then treating theproduct with a fixing agent.

7. The process which comprises treating cellulose acetate silk with agelling agent and with a solution of a wei hting agent comprising asuitablesalt ofadieavy metal,

then washing theproduct thus treated, and

then treating it with a fixingagent.

8. The process which comprises treating cellulose acetate silk with agelling agent and with'a solution of a weighting agent comprising asuitable salt of a heavy metal, then washing the product thus treated,then again treating with a gelling agent, and thereupon treating theproduct wit-ha fixing agent. 1 9. In the process of weighting celluloseacetate silk, the step which comprises treat ing the silk with a gellingagent.

10.,In the process of weighting cellulose acetate silk, the step whichcomprising treating the silk with a solution of a water solublealiphatic acid having a concentration of 15 to 20 per cent.

11. The process of weighting, cellulose acetate silk which comprisestreating the silk with a solution of a water soluble aliphatic acid andthen subjecting the so treated silk to the usual Weighting agents. x

12. The process of weighting artificial silk which comprises treatingcellulose acetate with a solution of a water soluble aliphatic acidhaving a concentration of not more.

than 20 per cent, and then subjecting the so treated silk to the actionof a solution of tin chloride.

13. The process of weightin artificial silk which consists in treatingcellulose acetate with a solution of a water soluble aliphatic acidhaving a concentration of 15 'to 20 per cent, subjecting the so treatedsilk to the action-of a solution of tin chloride, washing the silk withwater and subsequently treating the silk with a warm solutionof sodiumphosphate.

In testimony whereof I have aflixed my signature. I

GEORGE nivAr.

